5,554 research outputs found
Multiferroic properties of an \aa kermanite SrCoSiO single crystal in high magnetic fields
The magnetic and dielectric properties of \aa kermanite SrCoSiO
single crystals in high magnetic fields were investigated. We have observed
finite induced electric polarization along the c axis in high fields, wherein
all Co spins were forcibly aligned to the magnetic field direction. Existence
of the induced polarization in the spin-polarized state accompanied with the
finite slope in the magnetization curve suggests the possible role of the
orbital angular momenta in the excited states as its microscopic origin. The
emergence of the field-induced polarization without particular magnetic order
can be regarded as the magnetoelectric effects of the second order from the
symmetry point of view. A low magnetic field-driven electric polarization flip
induced by a rotating field, even at room temperature, has been successfully
demonstrated.Comment: 12 pages, 4 figure
Participation of Cbfa1 in regulation of chondrocyte maturation
AbstractObjective Cbfa1 is a transcription factor, which is classified into the runt family. The mice lacking this gene display complete loss of bone formation, indicating that Cbfa1 is an essential factor for osteoblast differentiation. The Cbfa1-deficient mice also show an abnormality in cartilage development. Although cartilage anlagens are well formed in these mice, endochondral ossification is blocked, and most of chondrocytes fail to differentiate into their maturation form as characterized by the absence of type X collagen and low levels of alkaline phosphatase activity. It is suggested that Cbfa1 may participate in chondrocyte differentiation. In this study, we have investigated the role of Cbfa1 in chondrocytes during their cytodifferentiation in vitro.Design To investigate the role of Cbfa1 in regulation of chondrocyte differentiation, we over-expressed Cbfa1 or its dominant negative form in cultured chick chondrocytes using a retrovirus (RCAS)system and examined changes in chondrocyte behaviour induced by the introduced genes.Results Mature chondrocytes isolated form the cephalic portion of sterna seemed to express Cbfa1 more prominently than immature chondrocytes isolated from the one-third caudal portion of sterna. Over-expression of Cbfa1 in immature chondrocytes strongly stimulated alkaline phosphatase activity and matrix calcification. In contrast, expression of a dominant negative form of Cbfa1, which lacks the C-terminal PST domain, severely inhibited alkaline phosphatase activity and matrix calcification in mature chondrocytes.Conclusion Taken together with the observation that Cbfa1 transcripts dominantly localized in hypertrophic chondrocytes as well as in osteoblasts, it is suggested that Cbfa1 plays an important role in the progression of chondrocyte maturation
2-4 Concluding Remarks(Discussions and Concluding Remarks,Session 2 : Surface Modification,SIMAP'88 Proceedings of International Symposium on Strategy of Innovation in Materials Processing-New Challenge for the 21st Century-)
Coffee inventory through orbital imagery
There are no author-identified significant results in this report
First-principles accurate total-energy surfaces for polar structural distortions of BaTiO3, PbTiO3, and SrTiO3: consequences to structural transition temperatures
Specific forms of the exchange correlation energy functionals in
first-principles density functional theory-based calculations, such as the
local density approximation (LDA) and generalized-gradient approximations
(GGA), give rise to structural lattice parameters with typical errors of -2%
and 2%. Due to a strong coupling between structure and polarization, the order
parameter of ferroelectric transitions, they result in large errors in
estimation of temperature dependent ferroelectric structural transition
properties. Here, we employ a recently developed GGA functional of Wu and Cohen
[Phys. Rev. B 73, 235116 (2006)] and determine total-energy surfaces for
zone-center distortions of BaTiO3, PbTiO3, and SrTiO3, and compare them with
the ones obtained with calculations based on standard LDA and GGA. Confirming
that the Wu and Cohen functional allows better estimation of structural
properties at 0 K, we determine a new set of parameters defining the effective
Hamiltonian for ferroelectric transition in BaTiO3. Using the new set of
parameters, we perform molecular-dynamics (MD) simulations under effective
pressures p=0.0 GPa, p=-2.0 GPa, and p=-0.005T GPa. The simulations under
p=-0.005T GPa, which is for simulating thermal expansion, show a clear
improvement in the cubic to tetragonal transition temperature and c/a parameter
of its ferroelectric tetragonal phase, while the description of transitions at
lower temperatures to orthorhombic and rhombohedral phases is marginally
improved. Our findings augur well for use of Wu-Cohen functional in studies of
ferroelectrics at nano-scale, particularly in the form of epitaxial films where
the properties depend crucially on the lattice mismatch.Comment: 10 pages, 7 figures, 3 tables, resubmitted to PR
DETERMINING AN EFFECTIVE STRETCHING TIME FOR ACHILLES TENDON EXTENSION
Stretching exercises are commonly undertaken for sports and rehabilitation. However, it is unknown how an in vivo muscle-tendon unit responds to added stretching stimulation. The purpose of this study was to determine an effective stretching time for Achilles tendon extension. The human medial head of the gastrocnemius muscle was stretched and ultrasonography was used to determine and then compare the length of the Achilles tendon between before and after stretching. Achilles tendon extension for one minute of stretching was 3.4±2.5mm, two 6.8±2.1mm, three 6.9±1.0mm, five 7.2±0.7mm, and ten 7.4±0.8mm. Achilles tendon length was significantly increased for up to two minutes of stretching (
Circularly-Polarized Light Emission from Semiconductor Planar Chiral Photonic Crystal
We proposed and demonstrated a scheme of surface emitting circularly
polarized light source by introducing strong imbalance between left- and
right-circularly polarized vacuum fields in an on-waveguide chiral grating
structure. We observed circularly polarized spontaneous emission from InAs
quantum dots embedded in the wave guide region of a GaAs-based structure.
Obtained degree of polarization reaches as large as 25% at room temperature.
Numerical calculation visualizes spatial profiles of the modification of vacuum
field modes inside the structure with strong circular anisotropy.Comment: REVTeX4.1, 6pages, 3figure
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